JPH0256241B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an auxiliary heating device for an automobile air conditioner that can quickly supply warm air into a vehicle interior during a cold start of an engine. be.

(Conventional example) In an automobile air conditioner, as a device for heating air, engine cooling water is guided into a heater core provided in an air conditioning case, and the cooling water exchanges heat through the heater core to generate warm air. I was getting it.

However, when the engine is cold, the temperature of the cooling water is low, so naturally it cannot function as a heater, and it is necessary to wait until the engine warms up. This means that moving the vehicle in the winter is cold and painful.
There was a need for a heater that provided immediate effects.

As a countermeasure, as shown in Japanese Utility Model Application No. 57-127116, a device that warms the cooling water using a combustion type heater has been proposed, but it takes time to warm up the cooling water. This has the disadvantage that it takes time for hot air to be blown out.

For this reason, the applicant proposed adding an auxiliary heating device in addition to the heater core, which is warmed by engine cooling water, so that hot air can be blown out immediately even when the engine is cold. This auxiliary heating device obtains intake air from upstream of the intake manifold and returns combustion gas to the downstream of the intake manifold, so that the intake passage and the exhaust passage are formed as if to bypass the intake manifold. The amount of air taken into the auxiliary heating device fluctuates depending on the engine speed, resulting in unstable fuel combustion, and in the worst case, the combustion flame may be blown out.

(Objective of the Invention) Therefore, an object of the present invention is to stabilize the combustion of fuel in an auxiliary heating device that can immediately blow out warm air when the engine is cold.

(Means for Achieving the Object) The gist of the invention is to supply fuel with a pump, take in air from upstream of the intake manifold, and return exhaust gas to the downstream of the intake manifold. In an auxiliary heating device for an automobile air conditioner, the capacity of the pump is made proportional to the engine speed.

(Achievement of purpose) Therefore, since the capacity of the fuel supply pump is increased or decreased relative to the engine speed, the air-fuel ratio is always constant and combustion is stabilized.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, to first explain the automotive air conditioner, an outside air inlet 2 and an inside air inlet 3 are formed in the most upstream side of an air conditioning case 1 in the form of two branches, and an inside/outside air switching door 4 is installed at the branch point. The air to be introduced into the air conditioning case 1 can be selected between inside air and outside air using the inside/outside air switching door.

The blower 5 is for sucking air into the air conditioning case 1 and blowing it to the downstream side.
An evaporator 6 and a heater core 7 of a heat exchange device 8 are provided on the downstream side.

The evaporator 6 cools the introduced air, and includes a compressor, a condenser, and a condenser (not shown).
A cooling cycle is configured together with the liquid tank and the expansion valve, while the heater core 7 heats the introduced air and is inserted into a hot water cycle in which cooling water for the engine 20 is circulated.

An air mix door 9 is located in front of the heater core 7.
is provided, and this air mix door 9 is
The ratio of air passing through the heater core 7 to air not passing through the heater core 7 is determined by its opening degree, and is operated via an actuator (not shown) or the like.

Furthermore, the downstream side of the air conditioning case 1 includes an upper outlet 10, a lower outlet 11, and a defrost outlet 12.
are connected, and each opens into the passenger compartment. A mode door 13 is arranged at the branch point between the upper outlet 10 and the lower outlet 11, and
The lower air outlet 11 has a mode door 14 which should cause air to flow to the defrost air outlet 12.
are arranged. The rotation control of the blower 5, the drive control of the compressor, and the opening degree control of the air mix door 9 are controlled as appropriate by outputs from a control unit (not shown).

One end 15a of the auxiliary heating passage 15 opens into the air conditioning case 1 downstream of the blower 5, and a door 16 for opening and closing is provided at the connection part. Also,
The other end 15b of the auxiliary heating passage 15 is downstream of the heat exchange device 8 and is connected to the lower outlet 11 on the upstream side of the position where the defrost outlet 12 is connected. Note that the other end 15 of the auxiliary heating passage 15
The connection b may be connected upstream of the mode door 13 for switching between the upper outlet 10 and the lower outlet 11. In addition, the door 1
6, when the auxiliary heating device 17 described below is activated, it is moved as shown by the solid line, and the auxiliary heating passage 15 is opened. In the middle of the auxiliary heating passage 15, an auxiliary heating device 17 described below is arranged.

The engine 20 is a diesel engine for driving, and is provided with an intake manifold 21 and an exhaust manifold 22. Air is sucked into each cylinder via an air cleaner 24 provided at the tip of the intake manifold 21, and air is sucked into each cylinder. Fuel is injected into the engine through the injection valve 25, and the fuel explodes due to the heat generated during the compression stroke, which is output as mechanical energy through the piston and crankshaft. At this time, the generated thermal energy is cooled by the cooling water of the engine 20 and discharged to the outside of the vehicle by the radiator 26, and a part of it is sent to the heater core 7.

The auxiliary heating device 17 has a configuration as shown in FIG. 2, for example, and includes a combustion device 27 and an auxiliary heat exchanger 28, and a burner 35 such as a nozzle and a wick of the combustion device 27 is arranged in a combustion chamber 29. Fuel is in tank 3
When supplied, the fuel is ignited by an ignition device 32 such as a spark plug or glow plug, and combusted in the combustion chamber 29. Combustion in the combustion device 27 is performed by detecting cold start from the engine cooling water temperature, outside air temperature, etc., and under predetermined conditions (for example, when the cooling water temperature is 55°C or lower and the outside air temperature is 10°C).
(below), and the combustion period, that is, the use time of the auxiliary heating means device, continues until the engine cooling water temperature rises sufficiently and heating can be performed by hot air.

The pump 31 is of a variable capacity type, and in the case of a diaphragm type or plunger type, it is controlled by increasing or decreasing the stroke amount or by increasing or decreasing the number of strokes, and if it is a rotary type, it is controlled by increasing or decreasing the number of rotations. The capacity of the pump is adjusted in comparison to the engine rotation speed, and its specific configuration includes an engine detector 36 that detects the engine rotation speed, and an engine detector 36 that processes this rotation signal and outputs an appropriate drive signal. It consists of a control circuit 37.

Although an independent pump is shown as the pump 31, in a diesel engine, the pressure within the chamber of a fuel injection pump may be utilized.

The combustion chamber 29 is connected to the upstream side of the intake manifold 21 via an intake passage 33 that takes in air, and is connected downstream of the intake manifold 21 to an exhaust passage 34 that discharges exhaust gas. Therefore, the combustion chamber 29 in both passages 33, 34 is provided in parallel with the intake manifold 21, and in order to receive engine negative pressure, the combustion chamber 29 in both passages 33, 34 (intake (It serves as a bypass passage.)
Air is introduced into the combustion chamber 29 through the combustion chamber 29.

Further, the auxiliary heat exchanger 28 includes the combustion chamber 2
The air flowing through the auxiliary heating passage 15 is heated by the auxiliary heat exchanger 28 and flows out through the auxiliary heating passage 15.

In the above configuration, when the heater mode is set in winter and the blower 5 is rotated to use the heater, the auxiliary heating device 17 is activated when the engine cooling water temperature is low. That is, the pump 31 is driven to supply fuel, the ignition device 32 is heated, and the fuel is combusted. At this time, air for combustion is taken in from the intake manifold 21 via the intake passage 33, and exhaust gas generated during combustion is returned to the intake manifold 21 from the exhaust passage 34.

Then, the door 16 is switched, and the air introduced by the rotation of the blower 5 is flowed into the auxiliary heating passage 15 and flows into the auxiliary heat exchanger 28 of the auxiliary heating device 17, where it is heated and becomes hot air, resulting in auxiliary heating. Passage 1
5 to the air conditioning case 1, and is blown out from the lower air outlet 11 into the vehicle interior.

Since the fuel supply capacity of the pump 31 is increased or decreased in proportion to the engine speed, the amount of air introduced into the auxiliary heating device 17 is proportional to the engine speed, and the best air-fuel ratio can always be obtained. It can prevent incomplete combustion and blowout of exhaust gas.

Note that as the engine speed increases, the capacity of the pump 31 increases, so the amount of heat radiation increases, but the maximum amount of heat radiation is determined for safety.

The amount of fuel to be supplied is arbitrarily determined in consideration of conditions such as the volume of the vehicle interior and the outside temperature.

(Effects of the Invention) As described above, according to the present invention, since the fuel supplied to the auxiliary heating device is increased or decreased in proportion to the engine speed, the air-fuel ratio can always be kept constant, and It can prevent burning and blowing out.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of this invention;
The figure is a detailed view of the auxiliary heating device. 1...Air conditioning case, 5...Blower, 8...Heat exchange device, 10...Upper outlet, 11...Lower outlet, 12...Defrost outlet, 15...Auxiliary heating passage, 17...Auxiliary heating device, 21...Intake manifold, 3
1...Pump, 33...Intake passage, 34...Exhaust passage.

Claims (1)

[Claims] 1. In an auxiliary heating device for an automobile air conditioner in which fuel is supplied by a pump, air is taken in from upstream of the intake manifold, and exhaust gas is returned to the downstream of the intake manifold, the capacity of the pump is adjusted to match that of the engine. An auxiliary heating device for an automobile air conditioner, characterized in that the heating is proportional to the rotational speed.